Anti-terror police were today renewing their questioning of 14 people arrested in dawn raids.

The arrests were made in London, Cambridge, Walsall, Dudley and Luton in swoops on homes and businesses.

Twelve men and two women are being held in custody under the Terrorism Act but Scotland Yard said they were not linking the raids.

Another suspect is still be held at a top-security police station in central London.

Sajid Badat, 24, a British Muslim, was detained in Gloucester last week by detectives investigating a possible al Qaeda link.

Yesterday's developments came as Tony Blair warned Britain to remain vigilant and the Foreign Office said Britons in Saudi Arabia faced the risk of fresh terrorist attacks.

Armed police raided six houses and three businesses in south west London. A 28-year-old, two aged 29 and one aged 32 were taken to central London police stations for questioning.

In Cambridge officers raided an address where three men and two women were arrested under Section 41 of the Terrorism Act 2000. Another man was arrested later at a separate address.

All were taken to a Cambridgeshire police station for questioning.

Police conducted a finger-tip search of the premises.

And in a separate development, West Midlands Police said four men were arrested under the Terrorism Act at premises in Dudley, Walsall and Luton.

The raids came after anti-terrorist operations were launched in Gloucester, Manchester, Birmingham and Blackburn last week.

Under the Terrorism Act, police have a maximum of seven days to hold the four men without charge.

NA man of North African origin was appearing at Bow Street Magistrates' Court in London today charged with a terrorism offence.

Noureddinne Mouleff, 36, of Eastbourne, was arrested last week and is charged under Section 57 of the Terrorism Act, namely being in possession of articles or items in connection with an act of terrorism.

He has also been charged with conspiring with others to defraud clearing banks.